Liquid fuel heaters



June 28, 1966 B. T. D. MARTIN 3,258,056

LIQUID FUEL HEATERS Filed Aug. 21, 1962 s Sheets-Sheet 1 Z lgg/ K 7 z/aa/a 054 x w a 5 June 28, 1966 B. T. D. MARTIN 3,258,056

LIQUID FUEL HEATERS Filed Aug. 21, 1962 5 Sheets-Sheet 2 June 28, 1966 B. T. D. MARTIN 3,258,056

LIQUID FUEL HEATERS Filed Aug. 21, 1962 3 Sheets-Sheet 3 7I/5P/WOC PZ United States Patent 3,258,056 LIIQUID FUEL HEATERS Bernard Thomas David Martin, Maywick Appliances Ltd, Wickford, England Filed Aug. 21, 1962, Ser. No. 218,298 Claims priority, application Great Britain, Aug. 21, 1961, 30,105/61; Sept. 22, 1961, 34,102/61; Dec. 5, 1961, 43,602/61, 43,604/61; May 15, 1962, 18,755/62 5 Claims. ((Zl. 158-365) The invention relates to liquid fuel heaters and particularly to heaters using liquid fuels such as kerosene.

In such heaters ancillary equipment is generally required to pre-heat the burner of the heater and in operation a compressor or the equivalent is normally required to maintain the supply of liquid fuel to the burner.

It is a disadvantage that pre-heating requires either means for supplying a readily combustible substance as, for example, a liquid fuel such as methylated spirit, or else a carrier to enable some of the liquid fuel used in the operation of the burner to be ignited around the burner. Thus, for example, cloth or waste soaked in kerosene is frequently used to effect the pre-heating of a kerosene heater.

It is a further disadvantage of such pre-heating means that carbon deposits are formed which may block the jets of the burner nozzle and either lessen the efliciency of the heater or render it inoperative.

The provision of a compressor or the equivalent to maintain the supply of fuel during operation adds to the cost of the apparatus.

It is among the objects of the invention to overcome these disadvantages.

According to the invention means are provided in a heater whereby a liquid fuel, such as kerosene, capable of combustion under pressure or by forced draught is initially pre-heated and then pressurised by a combustible gas such as a liquid petroleum gas.

Thus, for example, in application to a heater using kerosene the pre-heating of the liquid fuel may be effected by heating the burner nozzle by combustion of propane, supplied under pressure from a container of the gas in liquefied form, the pressure of uncombusted propane in the container being effective, after the pre-heating is completed, to maintain a supply of kerosene to the burner nozzle for vapourisation and combustion.

Furthermore in a heater according to the invention valve means may be provided for the simultaneous supply with the liquid fuel of a combustible gas such as propane for heating the nozzle of the burner to maintain the flame burning and control means, advantageously thermostatic control means, automatically operable to increase the supply of the combustible gas should the flame die down.

It is a further feature of the invention that the supply of the gas may be maintained throughout operation to ensure that there is no flame failure or deposit on the burner elements through cracking of the gas.

To effect improved combustion of the liquid fuel during operation of the heater the liquid fuel may be fed to a closed circuit in the burner of the heater so that the heat from the burner heats the liquid fuel during its passage through the closed circuit to the burner nozzle.

An initial pre-heating of the burner is effected by burning at or adjacent to the burner nozzle a combustible gas led from a container of the gas under pressure, after which initial pre-heating the supply of gas is turned off, reduced, or switches to pilot control, the pressure of the combustible gas still in the container being utilised to force the liquid fuel through the liquid flow line to a jet or jets in the burner.

It will be appreciated that by heating the liquid fuel 3,258,956 Patented June 28, 1966 as it passes through the burner head vaporisation and combustion is improved.

Thus according to the invention a burner for the heater may be formed with a head having a gas jet or nozzle and a liquid fuel jet or nozzle the combustible gas being first ignited at the burner nozzle to provide a flame which effects pre-heating'of the liquid fuel nozzle, so that the liquid fuel after combustion has started is readily ignited and, being led through the head or coil of the burner, is heated before reaching the burner nozzle.

According to the invention furthermore there are provided in a heater means for stabilising the flame from the burner, means for regulating the supply of air to the burner, and filter means in the liquid fuel jet or jets.

Thus the means for stabilising the flame from the burner may comprise a tubular member disposed substantially in the plane of the flame from the burner and inclined to the directions of the flame so as to deflect, direct and concentrate the flame on that part of the burner where maximum heat is required.

In application of the method according to the invention to a space heater means are provided for effecting concentration of the heat from the burner of the heater into a combustion chamber as, for example, a tubular member from which heat is passed by convection through an annular space surrounding the chamber from which space it passes to atmosphere through a surrounding guard or grid formed of Wire mesh or the like.

Alternatively the heat from the burner or burners of the heater may be caused to pass through a perforated part of the wall of the combustion chamber, so that the perforated part becomes incandescent and heating is effected both by radiation and by convection. Advantageously heat passing from the combustion chamber to atmosphere may be entrained with air driven through the annular space around the combustion chamber by fan means.

The invention is illustrated by way of example in the accompanying diagrammatic drawings in which:

FIGURE 1 is a schematic diagram illlustrating the layout and the gaseous and liquid fuel circuits used in operation of the invention;

FIGURE 2 is a perspective view of a burner used in operation of the invention the burner head incorporating a coil and stabiliser.

FIGURE 3 is a plan from above of the burner head shown in FIGURE 2;

FIGURE 4 is a sectional view of a burner and stabiliser used in operation of the invention the burner head being formed by plates disposed in spaced relation and FIGURE 5 illustrates schematically the layout for utilising the method of the invention in an industrial space heater.

FIGURE 6 is a detailed schematic illustration of the operation of valve G, illustrated in FIGURE 1.

Referring to FIGURE 1 of the drawings, operation according to the invention is as follows:

A liquid fuel, such as kerosene, is contained in a con taine-r 1, to which a combustible gas, such as propane is fed at 2 from a container 3 the gas in the container being under pressure as for example in the liquid state.

A by-pass line 4 for providing the gas to the burner of the heater is provided. The liquid fuel is supplied to the burner through line 5. Valves, taps, or the equivalent denoted by A, B, C, D, E, F, G are provided for control purposes in the supply lines of the combustible gas and of the liquid fuel.

In operation a supply of combustible gas through line l is first turned on ignited at the burner and the supply maintained until the burner head of the heater reaches the required temperature for ignition of the liquid fuel.

The line 5 is then opened to supply liquid fuel to the burner and the line 4 is wholly or partially closed depending on operational requirements.

The supply of liquid fuel to the burner is maintained by pressure at 2 of the gas in container 3 on the liquid in container 1.

To prevent flame failure at the burner, thermostatic control means which may comprise a flame control valve, a magnetic valve or solenoid indicated schematically and denoted G in FIGURES 1 and 6 of the drawings operates automatically as and when required to ensure a flow of combustible gas sufficient to maintain the flame of the liquid fuel at the burner.

The valve illustrated schematically and denoted D in the drawings is provided to ensure that at the end of combustion if the liquid fuel in the supply line or in the burner is not exhausted the supply of liquid fuel from 1 may be turned off at valve E and by closing valves A and C gas from 3 may be directed through the liquid fuel line to flush the line and burner and purge the burner of carbon or other products of combustion which may have accumulated during combustion.

In the burner illustated in FIGURES 3 and 4 gas is first fed through line 4 to a gas jet 7 and ignited, combustion being continued until the liquid fuel jet 8 is heated sufficiently to ensure combustion of the liquid fuel which is forced through line 5 and coil 6 by pressure of the gas at 2 on the liquid fuel in 1, the valve A being opened to permit this pressurising of the liquid fuel supply.

After ignition of the liquid fuel at jet 8 the supply of combustible gas may either be turned off, reduced, or switched to pilot control as required.

The flame from the liquid fuel jet 8 is directed by means of the stabiliser 9 which is so disposed that the flame is concentrated and controlled and heat from the burner head is directed at an inclination on to the burner coils to ensure maximum heating of the burner coil. The stabiliser is disposed substantially in line with the flame issuing from the jet but at an inclination to the direction of the flame is indicated in FIGURE 3.

In the burner shown in FIGURE 4 gas is fed through line 4 to gas jet 7, 'where it is ignited to effect preheating of the burner. When the liquid fuel jet is sufliciently heated to ensure ignition and combustion of the liquid fuel line 5 is opened and the liquid fuel led through tube 10, space 11, and tube 12 to the jet 8 where it is ignited the flame being directed and concen trated by means of a stabiliser disposed as hereinbefore described in relation to the flame.

It will be appreciated that in both constructions of burner the liquid fuel is heated as it passes to the burner nozzle and that improved combustion is thereby effected.

A draught regulator plate, not shown in the drawings, adapted to be movable along the burner feed lines and to be clamped in a determined position may be provided so that the flow of air to the burner may be varied if required.

FIGURE 5 illustrates schematically operation of the method and means according to the invention in a space heater.

In the drawing 13 denotes a burner or burners as hereinbefore described, mounted in a combustion chamber 14 of cylindrical form with a closed conically shaped end and mounted in a container 15. Part 16 of the combustion chamber may be formed of perforated sheeting. Fan means denoted by 17 in the diagram may be utilised to increase the dispersion of the heat from the combustion chamber 1. The burners are pre-heated by a combustible gas and operate on a liquid fuel pressurised by the gas as hereinbefore described to heat the chamber 14.

The heat from the burners on passing along the chamber 14 to the closed end is forced outwardly and passes through the perforations of part 16 and in so doing causes the temperature of the perforated part to rise to incandesence and to radiate heat into the annular space surrounding the combustion'chamber. Heat transfer is therefore effected both by convection and by radiation.

I claim:

1. A heater comprising a liquid fuel burner, a liquid fuel supply, a liquid fuel supply line connected between said liquid fuel burner and said liquid fuel supply, a combustible gas burner, a combustible gas supply, a pressurized combustible gas supply line connected between said combustible gas burner and said combustible gas supply, a first connecting line between said combustible gas supply and said liquid fuel supply, a second connecting line between said liquid fuel supply line and said combustible gas supply line, and valve means in said first and second connecting lines and said liquid fuel and combustible gas supply lines, said valve means permitting said combustible gas to be directed through said liquid fuel supply line to said liquid fuel burner thereby purging said liquid fuel supply line.

2. A heater comprising a liquid fuel burner, a liquid fuel supply, a liquid fuel supply line connected between said liquid fuel burner and said liquid fuel supply, said liquid fuel supply line having first and second valves therein, a combustible gas burner, a combustible gas supply, a pressurized combustible gas supply line connected between said combustible gas burner and said combustible gas supply, said combustible gas supply line having first and second valves therein, a first connecting line between said combustible gas supply and said liquid fuel supply, said first connecting line having a valve therein, a second connecting line positioned between said first and second valve in each of said liquid fuel and combustible gas supply lines, said second connnecting line having a valve therein, whereby upon closing said first valve of said liquid fuel supply line, said first connecting line valve, and said second valve of said combustible gas supply line, combustible gas is directed through said liquid fuel supply line to said liquid fuel burner thereby purging said liquid fuel supply line.

3. A heater as claimed in claim 1 wherein said valve means in said connecting lines and said liquid fuel and combustible gas supply lines are remote from said liquid fuel burner.

4. A heater as claimed in claim 1 including control means for controlling the successive or simultaneous supply of combustible gas and of liquid fuel for combustion.

5. A heater as claimed in claim 4 wherein said control means includes thermostatic means automatically operable to ensure a supply of combustible gas suflicient to maintain the flame of the liquid fuel burner.

References Cited by the Examiner UNITED STATES PATENTS 227,695 5/1880 Lyman 158-62 404,063 5/1889 Wallwork et al.

651,606 6/1900 Johnson et al. 158-62 X 658,794 10/1900 Loeben 158-50.1 X

882,611 3/1908 Barthel 158-61 1,139,922 5/1915 TesCh 158-11 1,280,425 10/1918 Duket 158-62 1,633,175 6/1927 Gieseke 158-53 1,638,434 8/1927 Curme, et al. 158-53 X 1,914,133 6/1933 Kerr 158-81 2,676,846 4/1957 Loose 158-81 X 2,966,945 1/1961 Downs 263-19 X 3,049,168 8/1962 Litwinoff 158-11 3,062,271 11/1962 Rijnsdorp 158-11 3,077,343 2/1963 Mohn 239-19 FREDERICK KETTERER, Primary Examiner. JAMES W. WESTHAVER, Assistant Examiner. 

1. A HEATER COMPRISING A LIQUID FUEL BURNER, A LIQUID FUEL SUPPLY, A LIQUID FUEL SUPPLY LINE CONNECTED BETWEEN SAID LIQUID FUEL BURNER AND SAID LIQUID FUEL SUPPLY, A COMBUSTIBLE GAS BURNER, A COMBUSTIBLE GAS SUPPLY, A PRESSURIZED COMBUSTIBLE GAS SUPPLY LINE CONNECTED BETWEEN SAID COMBUSTIBLE GAS BURNER AND SAID COMBUSTIBLE GAS SUPPLY, A FIRST CONNECTING LINE BETWEEN SAID COMBUSTIBLE GAS SUPPLY AND SAID LIQUID FUEL SUPPLY, A SECOND CONNECTING LINE BETWEEN SAID LIQUID FUEL SUPPLY LINE AND SAID COMBUSTIBLE GAS SUPPLY LINE, AND VALVE MEANS IN SAID FIRST AND SECOND CONNECTING LINES AND SAID LIQUID FUEL AND COMBUSTIBLE GAS SUPPLY LINES, SAID VALVE MEANS PERMITTING SAID COMBUSTIBLE GAS TO BE DIRECTED THROUGH SAID LIQUID FUEL SUPPLY LINE TO SAID LIQUID FUEL BURNER THEREBY PURGING SAID LIQUID FUEL SUPPLY LINE. 